Added version requirement.

Author: aparajita

README.md

@@ -18,6 +18,8 @@ Before installing this plugin, you must ensure that `csslint` is installed on yo
 
 1. If you are using `nvm` and `zsh`, ensure that the line to load `nvm` is in `.zshenv` and not `.zshrc`.
 
+**Note:** This plugin requires `csslint` 0.10.0 or later.
+
 ### Linter configuration
 In order for `csslint` to be executed by SublimeLinter, you must ensure that its path is available to SublimeLinter. Before going any further, please read and follow the steps in [“Finding a linter executable”](http://sublimelinter.readthedocs.org/en/latest/troubleshooting.html#finding-a-linter-executable) through “Validating your PATH” in the documentation.
 

linter.py

@@ -19,6 +19,9 @@ class CSSLint(Linter):
 
     syntax = ('css', 'html')
     cmd = 'csslint --format=compact'
+    version_args = '--version'
+    version_re = r'v(?P<version>\d+\.\d+\.\d+)'
+    version_requirement = '>= 0.10'
     regex = r'''(?xi)
         ^.+:\s*   # filename